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So the settling time is similar for either condition.
Do you measure the offset across a load (headphone), or with no load resistance other than the DMM ? Does it make a difference ? The worst case scenario for offset is into low impedance, high efficiency cans like Grados. Do you get that kind of offset spike on turn on, measured across a 30 ohm load or only across an open circuit ?
Thanks. That's three that have landed. I sent sachu's to the wrong address and ujamer and cobalt are waiting on Canadian post. Just checking.
Well I certainly did not perform those measures with my pristine HF-2's plugged into the amp! I suspect the results would be the same, but , perhaps Alex can chime in with the correct answer.
So, to answer your question, I did not measure under load. Now, if you want to loan me your grado's, I would be more than happy to repeat the tests under load for you.
I suppose I could slap a resistor across the output to simulate, but, I would rather not and just take the open measure as a baseline reference. I don't believe it is a big issue with this amp, just don't plug in your phones until it has a chance to settle. Either that or build a couple epsilon 12's and rest assured.
I've been "burnt" by offset issues a couple times.
hah..well seems the boards got forwarded to a friend's address. Gonna receive them tomorrow and the parts should get delivered same day as well. word up!!
Looks like sachu and ujamerstand are gonna have a busy weekend.
If you don't mind me asking, what happened? Did you lose a decent set of phones?
Anyone have any good reason not to use CMF55 for all the resistor choices? 1/2W at 70C like the 1/2W BOM resistors, exactly the same part as the RN55 and you can get a slightly better tempco part for slightly cheaper than the BOM RN55.